Coping with deeper well conditions
The Variseal® 600 and 700 series seals are suitable for groove depths from 0.49 inch and 0.685 inch/ 12.5 mm and 17.4 mm, supporting up to 0.197 inch/ 5 mm of hardware deflection. In deeper wells, higher pressures and temperatures cause a higher level of hardware separation. The larger single spring of the Variseal® 600 and 700 series can absorb this greater separation without loss of sealing performance.

John Findlay, Product Manager at Trelleborg Sealing Solutions facility in Bridgwater, England, where the seals are made, says: “Starting out on the design of the Turcon® Variseal® 600 and 700 series required thorough analysis and validation of our existing products, producing 3D CAD solid modelling and detailed FEA modelling, supported by our global R&D network, bringing unique insights to the table. But of course, this kind of theoretical testing cannot be taken alone, so we began extensive testing of the spring load performance to validate our FEA results.

Successful testing
“When these proved successful, physical testing of critical parameters of the entire spring and Variseal® assembly was undertaken, both in testing facilities and in situ on FPSO swivels. This has led to the development of a product that both Trelleborg and the customer know will outperform current seals in high pressure, extreme temperature applications.”

With all the flexibility and high performance that would be expected from a Variseal® spring-energized seal, the 600 and 700 series are available in a range of Turcon® grades, including NORSOK approved polytetrafluoroethylene (PTFE) based compounds and NACE compliant spring materials. Offering a wide operating range in rod, piston and axial designs, the seals can be individually tailored to suit specific applications. Inch conversions sizes, corner reinforcement and Back-up Rings are also available.